Field of Art
The present disclosure relates to a light source apparatus and an information acquisition apparatus using the same, and, in particular, relates to wavelength conversion and an amplification technique, which uses an optical parametric process.
Description of the Related Art
In molecular imaging of recent years, a technique for performing observations using short pulsed light as excitation light is being developed. In particular, research for performing imaging of selected molecular species by detecting the intensity of fluorescence caused by two-photon absorption or the intensity of stimulated Raman scattering have been studied actively. In performing such imaging, a light pulse that has a wavelength that matches the observation object is used as the excited light.
Light pulses with various wavelengths can be generated by utilizing wavelength conversion and amplification of light pulses through a nonlinear effect that occurs when the light pulse propagates inside a nonlinear optical waveguide. For example, Optics Letters, Vol. 38, No. 20, pp. 4154-4157, Oct. 15, 2013 (Non-Patent Literature 1) reported a method using an optical parametric process during four-wave mixing inside a nonlinear optical waveguide as a method of achieving wavelength conversion to a light pulse having a narrow linewidth and a high output.
In wavelength conversion through four-wave mixing, two wavelength converted light pulses, namely, an idler beam that is a light pulse having a wavelength that is longer than that of the pump light pulse, and a signal beam that is a light pulse having a wavelength that is shorter than that of the pump light pulse are generated at the same time, and either one of the wavelength converted light pulses is extracted as an output pulse. In so doing, by synchronizing and inputting either one of the wavelength converted lights, that is, the idler beam and the signal beam, with the pump light pulse as a seed beam, energy conversion efficiency can be increased. That is referred to as a fiber optical parametric amplification (FOPA).